Gene that determines floral sex may be key to new hybrid seeds

October 31, 2016

A Yale University-led team of scientists has discovered a key gene in that controls the sex of maize flowers — a discovery that could open the door to creation of highly productive hybrid seed in many agricultural plants the authors say.

“Genetic control of floral sexuality is the gateway for extending hybrid systems to related cereal crops such as rice, sorghum and wheat,” said Stephen Dellaporta, professor of molecular, cellular, and developmental biology at Yale and senior author of the paper appearing Oct. 28 in the journal Science Advances.

Creating highly productive hybrid is already possible in corn because of a simple fact of biology — the male and female flowers are physically separated in different parts of the plant: the female ear and male tassel. Companies easily make maize hybrid seed by removing the tassel to create female plants, which when pollinated by nearby plants create valuable hybrid seed. These hybrid seeds produce dramatic increases in yield and are healthier and more resistant to disease.

However, most agricultural crops produce flowers with both male and female parts, making it difficult and expensive to create hybrids.

The Yale team isolated a key gene silkless 1, which when expressed in the plant programs all flowers to become female. Seeds produced on these female plants are entirely hybrid. This same process may be extended to related cereals, which in turn could be used to control the production of hybrid seeds, Dellaporta said.

“We need to double food production by 2050, and if we don’t come up with solutions the alternative will be widespread famine,” Dellaporta said. “Hybrid technology isn’t the entire answer, but is one important solution to increasing agricultural productivity of crops.”

Andrew Hayward of Yale is lead author of the study. Primary funding for the research was provided by the National Science Foundation and the Bill & Melinda Gates Foundation.